But here's a thought: How about just starting with the X-1 and working your way up?!! I saw an X-1A picture on your wall in one of your photos, that would be a cool ship too. So you could produce the X-1 and the X-1A in a combo pack. Okay, okay, I'm overloading, but I love the X-planes.
Any planes like those take months to plan and tool. Since I'm the only guy here, and I need income, the faster I can build up my kit line the better and then do the complicated stuff later on.
You might wonder how the X-2 is less complicated. Well it will require and nose cone and a small boat tail. A vacuum form turtle deck. Balsa wings and tails. The rest is built on a round BT60 body tube. This make it faster to produce.
The X-15 is very doable for the same reasons. It won't be scale but sports scale. But at a larger size very cool to have.
The X-1 I have built as an RC plane several times and again falls int the same category as the above mentioned. Same with the Sky Rocket.
Since you already have the facilities to make V2's, how about exploring some more variants? The obvious ones are the early A9 (horizontal fins extended right to the nose tip), A4b (winged, no cockpit, real prototype actually built) and Bumper WAC Corporal. Then there are the Russian sounding rockets based on the V2; the R-1a (basically a V2 with side pods), R-1ye (more interesting looking side pods and a specialised nose cone), R2 (externally looks like a stretched V2, internally totally different), R-2a (do to an R-2 what the R-1ye did to the V2).
Here's my scratch-built R-2a to give you some idea of what it looks like.